1. Field of the Invention
The present invention relates to a multi-stage type processing apparatus which can conduct processing such as development to a plurality of substrates at the same time.
2. Description of the Prior Art
Recently, trials of forming a thick film on a surface of a substrate have been performed. For example, it is necessary to form a resist film having a thickness of around 20 μm so as to form a protruding electrode, which is referred to as a bump, having a height of around 20 μm on a surface of an IC pattern by applying integrated circuit forming technology.
In addition, wire bonding, which has conventionally been used for mounting an IC chip on a substrate, requires labor and time because it is necessary to connect metal wires one by one in wire bonding. Thus, instead of wire bonding, there is another way, in which a plurality of metal posts are provided on a chip, and the chip is mounted on a substrate via the posts. Since the metal posts have a height of around 100 μm, it is necessary to form a resist film having a thickness of around 100 μm so as to form metal posts by applying integrated circuit forming technology.
It takes 3–30 minutes per substrate to conduct development processing to such a thick resist film. Therefore, there have been conducted trials of batch type processing in which 1 cassette (25 substrates) is immersed in a development tank at one time to reduce time for development. However, this type requires a great volume of developing liquid and also exchange of substrates.
Documents 1–3 disclose simultaneous cleaning of a plurality of substrates (wafers).
In Document 1, a cassette accommodating a plurality of substrates is set in a rotor which is driven by a motor, and the substrates in the cassette are cleaned while the rotor is being rotated.
Document 2 discloses a cleaning device which is comprised of a wafer cassette and a washing liquid ejection means. In this device, the wafer cassette has a disk body and a plurality of tubular members provided on the disk body at a predetermined interval, each tubular member having a spinner, and the washing liquid ejection means is a nozzle which is provided in each tubular member so as to be movable back and forward.
Document 3 discloses a system in which processing units, each unit comprising a cup and a chuck provided in the cup, are positioned in a multi-stage state in the vertical direction. Each chuck is rotated by drive force which is distributed from a drive shaft provided in the vertical direction by using a timing belt, and substrates are exchanged by elevating and lowering the chuck.
Document 1: Japanese Patent Application Publication Hei 6-163498
Document 2: Japanese Patent Application Publication Hei 6-216104
Document 3: Japanese Patent Application Publication 2000-49215 (paragraph 0034, FIGS. 4 and 7)
Applications of the devices disclosed in Document 1 and Document 2 enables simultaneous processing to plural substrates without using a great volume of developing liquid.
However, these devices are large in the lateral direction, and are not efficient in terms of space.
Also, in the device disclosed in Document 3, the chuck is elevated and lowered for exchanging substrates. Therefore, the chuck needs both a mechanism for elevating and lowering and a mechanism for rotating, thus the whole structure becomes complicated.